Stuff gate control



Nov. 2l, 1939.

A. ALLEN V2,180,656

STUFF GATE cNTRoL Filed Nov. 26, 1957 v 'l ml 7a 33 i Z0 27 Il 32 i INVENTOR Alberi Alien;

BY @mi 'QW Y Y ATTORNE Patented Nov. 21, 1939 UNITED STATES 2,180,656 STUFF GATE CONTROL Albert Allen, Sharon, Mass.,fassignorto The 4Fox- "boro Company, Foxboro,Mass., `a vcorporation of Massachusetts Application kNovember 26,.'1937, Serial No. 176,417

4 Claims.

This invention relates to-the control oi a stui gate of a paper-making machine, and in its more specific aspects, to apparatus for posi- `tioning the stuff gate from a remote station ad- 5 Vjacent paper-weighing apparatus usually located Aat the dry endofthe paper-making machine.

Generally speaking,the positioning of the stuff gate in the present practice of paper making is veiected manually by an operator who by a 0 lturn Wheel on the gate arbitrarily sets the gate to a position which he may deem proper fol- Ilowing a determination of the Weight of a sample ofthe paper coming from the dry end of the machine. Even though the paper weight may be off, an operator seldom resets fthe gate because of the effort involved in the back and forth travel between the distantly spaced stuff chest and the -Weighing machine, and the uncertainty of any adjustment the operator may make.

While certain attempts have been directed to devisingA automatic means for positioning the stuff gate in response to variations in certain properties of the paper affectedvby gate position, such as Weight, density, and thelike, such have not been entirely successful or practical, with the result that the industry still relies to a great extent on 'the unsatisfactory older practice o'f manuallypositioning the gate as above stated.

The present invention overcomes'the disadvantages of the prior practices in providing a simple, practical and reliable apparatus for positioning Vand recording the position of a stuii Vgate, the apparatus embodying a control which may be operated from a remote station 4ingapparatusgenerally located at the dry end of the machine. The improved apparatus comprehends vpower lmeans effective to open `and/or close the gate, with the control functioningto so adjust the power means as to position the stuff gate at a desired setting, and to maintain this position,` all as lcalled for, for example, by the weight of the paper coming from the dry end of the paper-making apparatus. "To this end a pneumatic system to actuate the gate is employed, the system utilizing a lsource of lowpressure air which may be the conventional mill air supply, and an air motor operatively related to the gate. Air from the source is supplied to the motor through a control head,with the control of the present system functioning responsive- 1y to its setting and to the position of the gate whereby to regulate the pressuresupplied through said control head to the air motor.

More specifically, the control of thepresent inventionutilizes an independent source'of. highgate position.

adjacentv the weigh- -to'themachine pressure-aina pressure-regulating means preferably 'located at the remotel control station ad- -jaoent weighing apparatus at'the dry end of the machine, and a Afrom yto a control instrumentality incorporating-5 regulated pressure line therefirst means frictionlessly responsive to the regulated pressure, second means movable in proportional correspondence to the gate, and third means correlating the ffirst and second means :with a control head so as to causelthe air motor,f10

through the control of pressure'supplied thereto, to position the gate in proportional correspondence-with vthe regulatedpressure as set bythe reducing valve aforesaid. rBy utilizing a regulating `valve especially designed to hold lated pressure within extremely close the regu- 515 limits regardless of variati-on in supply pressure, the gate is accuratelvpositioned and its position maintained by the system Aof the present invention. n Such a reducing valve isprovided with adjusting .20 means wherebyv different regulated pressures may be supplied tothe control instrumentality, thus Ato provide for different gate positions as required.

The invention further pro-vides for the recording of the'regulated pressure delivered by the 25 reducing valve. Such a record, `dueto the relation betweentheregulated pressure and the gate position, is by suitable translation a record of Thus, an operator at the control 'station remote from the position may set the 30 vreducing valvefor a desired pressure and by observing the pressurel record, is accurately advised of the gate'position. This record is also useful operator-fas a guide to the operation of the machine. Thus, if repeated resetting 35 is necessarvparticularly in one direction, there isindicated the existence of an abnormal condition orchange of condition in the. general operation of the machinav Again, a `record of the -actual weightofthe paper ysamp-les taken at conf venient time intervals, together with the record of the stuii gate position, gives a valuable check on the rgeneral machine performance.

Other objects will bein part obvious and in parthereinafter pointed out in connection with `4,5 the following analysis of this invention wherein is illustrated an 4embodiment of the invention in detail. l

v'In' the drawing:v Fig. 1 is aaschematicdiagram of stul gate 50 positioning apparatus ,and control therefor in accordance 'with the present invention; and,

Fig..2'is .asection through a pressure'reducing valve :formingfa part'of the control means illustrated in Fig.1.

Referring to the drawing, wherein like reference characters denote like parts throughout the views, reference character I designates a head box having a discharge opening Il for the flow of the pulp from the box to the web-forming apparatus, such arrangements being conventional and forming no part of the present invention. Flow of the pulp through the discharge opening Il is controlled by a stui gate I2 provided with a stem i3 which is adapted to be positioned by a gate-positioning element I4. In the construction illustrated, the upper end of the element I4 is provided with a turnbuckle I5 to which is connected the lower end of the stem I3, as by a pin I6, with the element I4 extending downwardly and axially of the stem and having its lower end operatively related to the diaphragm I1 of a pneumatic motor generally designated I8. With the gate biased to its closed position by a spring I9,

the arrangements and connections are such that movement of the diaphragm in response to air pressure is transmitted tothe positioning element I4, thence to the gate stem I3, and nally to the gate I2, thus to position the latter at Various ele- .-25 vations across the discharge opening II of the flow box Il). i

Pressure air is supplied to the motor I8 through an air line 22 connected through control head 2l with a supply line 26. The line 28 delivers to the P,30 interior of the control head 2I which is of the supply and waste type and which controls the pressure supplied to motor I8 through air line 22.

The control head -2I includes a double valve 23 carried by a stem 24 extending from diaphragm '35 25, the Valve controlling communication between lines 26, 22, and also a vent to atmosphere. Air is supplied from line 20 throughpa suitable restriction 21a to the interior of the diaphragm and to a nozzle element 26 of a control couple (including a flapper 28). The lapper in covering and uncovering the nozzle varies back pressure in diaphragm and the position of valve 23.

Considering now the mechanism of the' present invention by which the control head supplies such pressure to the motor as is necessary to insure the desired gate position, the stem positioning element I4 carries a collar 30 against which engages an arm 3l of a bell crank adapted to turn bodily on the xed axis of its cross arm 32, the other arm 33, which may be adjustable in length, engaging against and positioning one end of a control lever 34. A spring operative between a fixed abutment and an intermediate point of the lever 34 functions to yieldingly hold the lever 34 against bell crank arm 33 and arm 3| against collar 30.

Lever 34 forms one end of a bell crank which includes an offset cross link 45. The bell crank is suitably pivotally supported in spaced ears44 of a movable plate 43 suspended between a bellows 46 and an opposing spring 42. Regulated air pressure is delivered to the bellows through an air line 4I, and this pressure tends to distend the bellows against the bias of the spring 42 and so frictionlessly positions the plate 43 in correspondence with the pressure in the line 4I.

The bell crank has a second arm 46, the angular relationship of which with respect to arm 34 may be adjusted by means of screw 41 operative between the cross link 45 and the arm 46. The arm 46 terminates in an in-struck tongue 48 against which the flapper 28 is spring-pressed.

With this construction the pivoted end of lever arm 34 is frictionlessly positioned responsively to the controlled pressure in line 4I.

. gate position so established.

The lever 34 functions to correlate the action of the collar responsive to gate position with the means responsive to the regulated pressure according to a predetermined relationship. Thus, a particular pressure in the bellows 40 moves the fulcrum end of lever 34 to a particular position in correspondence therewith. Once this position is established, the lever through the action of its associated arm 46 on flapper 28 of the control couple, causes the control couple to so operate valve 23 that air is supplied to motor I8 at whatever pressure may be necessary to move the motor and gate I2 until its position, as measured by the bell crank arm 3|, is in correspondence with the position of the fulcrum end of the lever 34 as determined by bellows 46. So long as the particular pressure is maintained in the bellows, the control operating as described functions to maintain the Considering now the means for supplying regulated pressures to the bellows 46, whereby gate I2 may be positioned in proportional correspondence therewith, reference is had to Figs. l and 2, wherein a regulating valve 56 connected into the air line 4I is shown as arranged on a control panel 5I, which is preferably located at a control station remote from the gate and preferably adjacent the weighing apparatus generally located at or near the dry end of the machine. This location of the control station is desirable, as a sample of the web coming from the dry end of the machine can be weighed, and the control apparatus operated from this point to make such adjustments in the gate position as the weighed sample would indicate to be necessary.

In considering the regulating valvereference made to the fact that it is specially designed for dead end service as represented by the line 4I and bellows 4U, from which no air is bled as would necessitate a continuous or substantially continuous supply of air through the regulating valve to the dead end of the line. It is desirable too that the regulated pressure be held within close limits, regardless of variations in supply pressure.

To satisfy these requirements of dead end service, the regulating valve shown may be used. Referring to Fig. 2, a valve body is generally indicated at 52, having an inlet 53 into which is connected the air line 54 from a source of high pressure supply, and an outlet 55 into which is connected the air line 4I ending at bellows 46. Air from the high pressure line 54 passes into the chamber 56 in the valve body through a communicating passage 51. This passage is under the control of a valve 58 biased to a closing position on a seat member 60 by a spring 6I. Valve 58 has a stem assembly 63 extending axially of and through the passage 51. Adjacent the upper end of the stem assembly is a valve 64 operatively related to a seat member 65 having a through air passage 66.

Seat member 65 is carried by a diaphragm 61 secured between the body 52 and a bonnet member 68 arranged on the valve body. A diaphragm plate 16- serves to secure the seat member to the diaphragm and also forms a seat for an adjusting spring 1I adapted to exert pressure on diaphragm 61. The other end of the spring 1| reacts against a head carried by an adjusting screw 12 having a knurled operating knob 13.

Valve 64 is arranged in controlling relation to the passage 66 of the seat member 65, through which passage air from chamber 56 may pass to theinterior of bonnet 68 and-'thence to at- ,aft/warm Y 2 n v Fjjrlnfoff the Vstem *.12 and e benessere, offspring ".18 0111005601 bypth air ressurednlehamber 56 and by the gpgfsl tending to seatfvalve 58, and operates Ito adjust the `air lpressure in the chamber 56 until it is just sumcient to oppose spring ll and l move the valve stem assembly to a position in which both valve 58 and S4 are seated on their respective valve seats. Thus, changes in the upstream or high pressure do not affect the downstream or low pressure in the line 4| and bellows 40. If the downstream pressure tends to change due to leakage or to temperature, this pressure change operates diaphragm 6l and the two valves 58, B4 to bring back the downstream pressure to that corresponding to the pressure on the spring 1I.

From the above it will be seen that the pressure in the dead end or downstream side of the line is maintained at a substantially constant value as determined by the setting of the adjusting spring il, regardless of fluctuations of the supply pressure. The arrangement is further suc increase of the compression of the dead end pressure, andk compression of spring 1| de k pressure. Thus,

livered p .M-w-eerrowsw[ltlifigh line 4|, it follows that a record of this regulated pressure by suitable calibration constitutes a record of gate position. To provide such a record, a connection 80 from the line 4I to a recording instrument 8| is made, the recording instrument being preferably mounted on the control panel 5| and including a pressure-actuated pen recorder 82 by which a running record of the pressures in line 4I is made, thus to give a record of gate positions.

While a motor is shown for actuating and positioning the gate I2, under certain conditions as, for example, on failure of air, it may be necessary to actuate and position the gate manually. To this end the connection between the gate stem I3 and the positioning member i4 is made separable. By removing pin I6 the positioning member may be lowered, whereupon a hand wheel 95 threadedly carried by the gate stem may be r0- tated on the stem until it engages a Xed bracket or yoke member 96 through which the stem extends. Manipulation of the hand Wheel in either direction thereupon actuates the-gate l2 in opening or closing direction. This arrangement provides a simple means of converting from power to manual actuation and positioning of the gate I2. As many changes could be made in carrying I i;iutthe above constructions without departing that 11 Y, n l n l u I Eglinterpreted as illustrative and not 1n a llmitmg v shown intheaccompanying drawing shall I lclaim: 1,1m combination 'with a stuff gate, a u1 d pressure motor for actuating the gate, a u1d supply line to the motor, Control means for controlling the supply of fluid to said motor including first means frictionlessly responsive to a remote manual adjustment, second means responsive to gate position, and means for translating the action of said first and second means into control effects whereby said motor positions the gate in correspondence to the adjustment of said irictionlessly responsive means.

2. In combination with a stuff gate, a fluid pressure motor for actuating the gate, `a fluid supply line to the motor, a control head of the supply and waste type in the line, a control couple operatively related to the control head, and adjustable control means including first means frictionlessly responsive to the adjustment of the control means, second means responsive to gate position, and Vmeans for translating through the control couple the conjoint action of the first and second means to the control couple whereby the couple causesy uid to n e -o l mit 0l Ille Irre/M1011, 1l is mended llimiter ycanzm'lied,in the above descriv- .una uu v1.1 Juniuiuu u; uuu 111cm'- ber, a bellows having a free end, and means positionable irictionlessly in correspondence with the end of said bellows and also positionable in correspondence with ther means responsive to the position of the member and a pressure regulating valve located at a point remote from said member for maintaining the xed pressure in said bellows, said valve having manually adjustable means for setting the value of the pressure to be maintained. i

4. In combination with a stuff gate, a pneumatic motor for actuating the gate, a pressure air line Ato the motor, and control mechanism for causing said motor to actuate the gate to and maintain it ata position in correspondence with a predetermined value of air pressure comprising a pneumatic bellows member, means for supplying pressure air thereto, means located at a remote control station for setting the value of the pressure in the bellows, means responsive to gate position, a member positionable in accordance with the value of pressure in the bellows and the action of the gate-position-responsive means, and means for translating the position of said member into control effects on the value of the air pressure supplied to the motor.

ALBERT ALLEN. 

